Decision: Profile Streaming
Note: The following design decision only applies to those environments that use Citrix Profile Management.
With user profile streaming, files and folders contained in a profile are fetched from the user store (file server) to the local computer when a user accesses them. During the logon process, Citrix Profile
Management immediately reports that the profile load process has completed reducing profile load time to almost zero.
Citrix recommends enabling profile streaming for all scenarios. If it is desired to keep a local cached copy of the user profile, it is recommended to enable the “Always Cache” setting and configure a size of 0. This ensures that the user profile is downloaded in the background and enables the system to use this cached copy going forward.
Note: Profile streaming is not required and does not work with the personal vDisk feature of Citrix XenDesktop. Even if explicitly enabled by means of Group Policy, the profile streaming setting is
automatically disabled.
Decision: Active Write Back
Note: The following design decision only applies to those environments that use Citrix Profile Management.
By enabling the active write back feature, Citrix Profile Manager detects when an application has written and closed a file and copies the file back to the network copy of the profile during idle
periods. In scenarios where a single user leverages multiple virtual desktops or hosted shared desktops simultaneously, this feature can be tremendously beneficial. However, Citrix Profile
Management does not copy any registry changes back to the network, except during an ordered logoff. As such, there is a risk that the registry and files may get out of alignment on provisioned
systems, where locally cached profile information is wiped upon reboot. Therefore, it is recommended to disable active write back functionality for non-persistent Provisioning Services or Machine Creation Services scenarios.
Decision: Configuration Approach
Note: The following design decision only applies to those environments that use Citrix Profile Management.
Citrix Profile Management can be configured by means of an “.ini” file, Microsoft Group Policy and Citrix Policy (Citrix Profile Management 5.0 only). While each option offers the same configuration settings, Group Policy is recommended because it allows administrators to perform Windows and Citrix profile configurations from a single point, minimizing the tools necessary for profile management.
Note: With Citrix Profile Management 5.0, the desktop type is automatically detected and Citrix Profile Management policies set accordingly. For more information, please refer to Citrix eDocs –
How automatic configuration works.
Decision: User Profile Replication Between Datacenters
While having an active/active datacenter on a network level is easily accomplished with GSLB, the replication of user data makes having a fully active/active deployment complex in most situations. To
have an active/active configuration where users are not statically assigned to a specific datacenter, will require users to have no form of personalization requirements. This will limit the user’s ability to
make any configuration changes and will not allow them to create any documents or persistent data. The exception to this is when a high-speed low latency connection such as dark fibre is available between datacenters. This will let resources in both locations can point to the same file server allowing for a true active/active solution. Also, an active/active configuration can be accomplished when applications are used that rely solely on a backend database that is actively replicated between datacenters and do not store any data in the user profile.
For redundancy and failover purposes, user data such as Windows profiles and documents should be synchronized between datacenters. Although it is recommended to replicate user data between datacenters, the replication would be an active/ passive configuration. This means the data can only be actively consumed from a single datacenter. The reason for this limitation is the distributed file locking method inside Windows that only allows a single user to actively write to a file. Therefore, active/ active replication of user data is not supported. Any supported configuration consists of a one-way replication of data that is active in a single datacenter at any point in time.
For example, the figure below describes a scenario where user data is passively replicated from Datacenter A to Datacenter B. In this example, File Server A is the primary location for user data in
Datacenter A and File Server B is the primary location in Datacenter B. One-way replication of the user data occurs for each file server to allow for the user data to be available in the opposite datacenter if a failover occurs. Replication technologies such as Microsoft DFS can be configured to mirror user profiles and documents to a file server in another datacenter. DFS Namespaces can also be used to have a seamless path for the location of the user data.
User Policies
Citrix policies provide the basis to configure and fine tune XenDesktop environments, allowing organizations to control connection, security and bandwidth settings based on various combinations of users, devices or connection types.
When making policy decisions it is important to consider both Microsoft and Citrix policies to ensure that all user experience, security and optimization settings are considered. For more information on specific Windows related policies, please refer to the Microsoft white paper - Group Policy Settings Reference for Windows and Windows Server, specifically settings related to Windows Server 2008 R2, Windows 7, Windows Server 2012 and Windows 8. For a list of all Citrix-related policies, please refer to the Citrix Policy Reference spreadsheet.
Decision: Preferred Policy Engine
With XenDesktop 7 organizations have the option to configure Citrix policies via Citrix Studio or through Active Directory group policy using Citrix ADMX files, which extend group policy and provide advanced filtering mechanisms.
Using Active Directory group policy allows organizations to manage both Windows policies and Citrix policies in the same location, and minimizes the administrative tools required for policy management. Group policies are automatically replicated across domain controllers, protecting the information and simplifying policy application.
Citrix administrative consoles should be used if Citrix administrators do not have access to Active Directory policies. Architects should select one of the above two methods as appropriate for their
organization’s needs and use that method consistently to avoid confusion with multiple Citrix policy locations.
Decision: Policy Integration
When configuring policies, organizations often require both Active Directory policies and Citrix policies to create a completely configured environment. With the use of both policy sets, the resultant set of policies can become confusing to determine. In some cases, particularly with respect to Windows Remote Desktop Services (RDS) and Citrix policies, similar functionality can be configured in two different locations. For example, it is possible to enable client drive mapping in a Citrix policy and disable client drive mapping in a RDS policy. The ability to use the desired feature may be dependent upon the combination of RDS and Citrix policy. It is important to understand that Citrix policies build upon functionality available in Remote Desktop Services. If the required feature is explicitly disabled in RDS policy, Citrix policy will not be able to affect a configuration as the underlying functionality has been disabled.
In order to avoid this confusion, it is recommended that RDS policies only be configured where required and there is no corresponding policy in the XenDesktop configuration, or the configuration is specifically needed for RDS use within the organization. Configuring policies at the highest common denominator will simplify the process of understanding resultant set of policies and troubleshooting policy configurations.
